Integrated exhaust treatment device having compact configuration

ABSTRACT

An exhaust treatment device is disclosed. The exhaust treatment device has a compact configuration that includes integrated reactant dosing, reactant mixing and contaminant removal/treatment. The mixing can be achieved at least in part by a swirl structure and contaminant removal can include NO x  reduction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 13/795,443,filed Mar. 12, 2013, now U.S. Pat. No. 8,938,954, which applicationclaims the benefit of U.S. Provisional Patent Application Ser. No.61/635,677, filed Apr. 19, 2012, which applications are incorporatedherein by reference in their entirety.

BACKGROUND

Vehicles equipped with diesel engines typically include exhaust systemsthat have aftertreatment components such as selective catalyticreduction catalyst devices, lean NOx catalyst devices, or lean NOx trapdevices to reduce the amount of undesirable gases, such as nitrogenoxides (NOx) in the exhaust. For these types of aftertreatment devicesto work properly, a doser injects reactants, such as urea, ammonia, orhydrocarbons, into the exhaust gas. As the exhaust gas and reactantsflow through the aftertreatment device, the exhaust gas and reactantsconvert the undesirable gases, such as NOx, into more acceptable gases,such as nitrogen and oxygen. However, the efficiency of theaftertreatment system depends upon how evenly the reactants are mixedwith the exhaust gases. Example exhaust treatment devices are disclosedat U.S. Patent Publication Nos. US 2011/0167810; US 2010/0212301; and US2009/0000287. There is also a need for exhaust treatment devices thatare compact and that provide efficient and effective mixing ofreactants.

SUMMARY

The present disclosure relates generally to compact exhaust treatmentdevices that include integrated reactant dosing, reactant mixing andcontaminant removal/treatment.

A variety of additional aspects will be set forth in the descriptionthat follows. These aspects can relate to individual features and tocombinations of features. It is to be understood that both the foregoinggeneral description and the following detailed description are exemplaryand explanatory only and are not restrictive of the broad concepts uponwhich the embodiments disclosed herein are based.

DRAWINGS

FIG. 1 schematically depicts an exhaust treatment system in accordancewith the principles of the present disclosure;

FIG. 2 is a perspective view of an exhaust treatment device inaccordance with the principles of the present disclosure;

FIG. 3 is an end view of the exhaust treatment device of FIG. 2;

FIG. 4 is a cross-sectional view taken along section line 4-4 of FIG. 3;

FIG. 5 is a cross-sectional view taken along section line 5-5 if FIG. 4;

FIG. 6 is a cross-sectional view taken along section line 6-6 of FIG. 4;

FIG. 7 shows an exhaust flow path for the exhaust treatment device ofFIGS. 2-6;

FIG. 8 shows the exhaust treatment device of FIGS. 2-6 modified toinclude an additional swirling structure;

FIG. 9 shows the exhaust treatment device of FIGS. 2-6 modified toinclude an additional flow distribution structure;

FIG. 10 is an end view of a second exhaust treatment device inaccordance with the principles of the present disclosure;

FIG. 11 is a cross-sectional view taken along section line 11-11 on FIG.10;

FIG. 12 is a perspective view of a third exhaust treatment device inaccordance with the principles of the present disclosure;

FIG. 13 is an end view of the exhaust treatment device of FIG. 12;

FIG. 14 is a cross-sectional view taken along section line 14-14 of FIG.13;

FIG. 15 is a cross-sectional view taken along section line 15-15 of FIG.14;

FIG. 16 is a cross-sectional view taken along the section line 16-16 ofFIG. 14;

FIG. 17 is a cross-sectional view taken along section line 17-17 of FIG.14;

FIG. 18 is a cross-sectional view taken along section line 18-18 of FIG.14;

FIG. 19 is an end view of a fourth exhaust treatment device inaccordance with the principles of the present disclosure;

FIG. 20 is a cross-sectional view taken along section line 20-20 of FIG.19;

FIG. 21 is a cross-sectional view taken along section line 21-21 of FIG.20;

FIG. 22 is an end view of a fifth exhaust treatment device in accordancewith the principles of the present disclosure;

FIG. 23 is a cross-sectional view taken along section line 23-23 of FIG.22;

FIG. 24 is a cross-sectional view taken along section line 24-24 of FIG.23;

FIG. 25 is a perspective view of a sixth exhaust treatment device inaccordance with the principles of the present disclosure;

FIG. 26 is an end view of the exhaust treatment device of FIG. 25;

FIG. 27 is a cross-sectional view taken along section line 27-27 of FIG.26;

FIG. 28 is an opposite end view of the exhaust treatment device of FIG.25;

FIG. 29 is a cross-sectional view taken along section line 29-29 of FIG.27;

FIG. 30 is a cross-sectional view taken along section line 30-30 of FIG.27;

FIG. 31 is a cross-sectional view taken along section line 31-31 of FIG.27;

FIG. 32 is a cross-sectional view taken along section line 32-32 of FIG.27;

FIG. 33 is a perspective view of a seventh exhaust treatment inaccordance with the principles of the present disclosure;

FIG. 34 is an end view of the exhaust treatment device of FIG. 33;

FIG. 35 is a cross-sectional view taken along section line 35-35 of FIG.34;

FIG. 36 is a cross-sectional view taken along section line 36-36 of FIG.35;

FIG. 37 is a cross-sectional view taken along section line 37-37 of FIG.35;

FIG. 38 is a cross-sectional view taken along section line 38-38 of FIG.35;

FIG. 39 is a perspective view of an eighth exhaust treatment device inaccordance with the principles of the present disclosure;

FIG. 40 is an end view of the exhaust treatment device of FIG. 39;

FIG. 41 is a cross-sectional view taken along section line 41-41 of FIG.40;

FIG. 42 is a cross-sectional view taken along section line 42-42 of FIG.41;

FIG. 43 is a cross-sectional view taken along section line 43-43 of FIG.41;

FIG. 44 is a cross-sectional view taken along section line 44-44 of FIG.41;

FIG. 45 is a cross-sectional view taken along section line 45-45 of FIG.41;

FIG. 46 is an end view of a ninth exhaust treatment device in accordancewith the principles of the present disclosure;

FIG. 47 is a cross-sectional view taken along section line 47-47 of FIG.46;

FIG. 48 is a graph showing relationships between mixing volume, degreesof turbulence and NO_(x) conversion efficiency; and

FIG. 49 shows a mixing volume and expansion region of the embodiment ofFIG. 11.

DETAILED DESCRIPTION

Reference will now be made in detail to the exemplary aspects of thepresent disclosure that are illustrated in the accompanying drawings.Wherever possible, the same reference numbers will be used throughoutthe drawings to refer to the same or like structure.

Referring now to FIG. 1, an engine exhaust system, generally designated11, is shown. The engine exhaust system 11 includes an engine 13, a fueltank 15 for supplying fuel (e.g., diesel fuel) to the engine 13, an airintake 17, an air filter 19, and an exhaust conduit 21 for conveyingexhaust gas away from the engine 13. The engine exhaust system 11 alsoincludes an exhaust treatment device 23 in fluid communication with theexhaust conduit 21. The exhaust treatment device 23 includes a deviceinlet 30 that receives exhaust from the exhaust conduit 21 and a deviceoutlet 32 that directs treated exhaust to an exhaust conduit 34. Theexhaust conduit 34 carries the treated exhaust to an exhaust outlet 36in fluid communication with atmosphere. An exhaust treatment device suchas a diesel particulate filter (e.g., a flow-through filter, a wall flowfilter, etc.) or a diesel oxidation catalyst can optionally be providedupstream or downstream from the exhaust treatment device 23. Also, anoise abatement structure such as a muffler can be provided along theexhaust conduit 34.

The exhaust treatment device 23 is preferably configured to reduce theconcentration of NO_(x) (or other contaminants/pollutants) present inthe exhaust stream. In a preferred embodiment, the exhaust treatmentdevice 23 includes a treatment substrate for contaminants, particularlya NO_(x) treatment substrate 50 (e.g. a SCR substrate, a lean NO_(x)catalyst substrate, a lean NO_(x) trap or other structure) for removingNO_(x) (or other contaminants such as SO2, CO, VOCs, etc.) from theexhaust stream. The exhaust treatment device 23 also includes a doser 52(e.g., an injector, a spray nozzle, or other dispensing structure) thatsupplies a reactant (e.g., urea, ammonia, hydrocarbons or other reducingagents) suitable for reacting with NO_(x) (or other contaminants such asSO2, CO, VOCs, etc.) at the NO_(x) treatment substrate 50 to reduce theoverall concentration of contaminants such as NO_(x) in the exhauststream. The doser 52 is positioned upstream from the NO_(x) treatmentsubstrate 50. The exhaust treatment device 23 further includes a mixingarrangement 54 that generates turbulence (e.g., swirling) for assistingin mixing and volatilizing the reactant from the doser 52 before thereactant reaches the NO_(x) treatment substrate 50. In certainembodiments, the exhaust treatment device 23 includes an exhausttreatment substrate 56 positioned upstream from the mixing arrangement54. By way of example, the exhaust treatment substrate 56 can include acatalytic converter or a flow-through filter. The exhaust treatmentdevice 23 also includes contaminant sensors 58 (e.g., NO_(x) sensors)and temperature sensors 60. In the depicted embodiment, one set ofsensors 58, 60 is positioned adjacent the device inlet 30 and a secondset of sensors 58, 60 as positioned adjacent the device outlet 32. Ports58′ are contaminant sensor ports and ports 60′ are temperature sensorports.

It will be appreciated that the various components of the exhausttreatment device 23 are relatively positioned to provide a compactconfiguration. While the configuration is compact, the components areconfigured such that the reactants from the doser 52 are effectivelymixed and volatized prior to reaching the NO_(x) treatment substrate 50such that the NO_(x) treatment substrate 50 efficiently removes NO_(x)(or other contaminants such as SO2, CO, VOCs, etc.) from the exhauststream. In certain embodiments, the exhaust treatment device 23 has avolume less than or equal to 24 liters and is adapted to treat anexhaust flow up to 650 kilograms per hour at rated power. In otherembodiments, the exhaust treatment device has a volume less than orequal to 95 liters, and is adapted to treat an exhaust flow up to 1700kilograms per hour at rated power. In other embodiments, the exhausttreatment device has a volume less than or equal to 135 liters, and isadapted to treat an exhaust flow up to 2000 kilograms per hour at ratedpower. In still other embodiments, the ratio of the volume of theexhaust treatment device (liters) to the exhaust flow for which theexhaust treatment device is intended to treat (kilograms per hour atrated power) is in the range of 0.03 to 0.07. In certain embodiments,the upstream face of the NO_(x) treatment substrate 50 is spaced lessthan 750 millimeters from the doser 52. In other embodiments, theupstream face of the NO_(x) treatment substrate 50 is spaced in therange of 230-750 millimeters from the doser 52. Referring still to FIG.1, the exhaust treatment device 23 includes an outer housing 62including a length L that extends between first and second opposite endwalls 64, 66 of the outer housing 62. The outer housing also includes aside wall 68 that extends along the length L from the first end wall 64to the second end wall 66. In one embodiment, the side wall 68 iscylindrical, but elliptical shapes, oval shapes, rectangular shapes orother shapes could also be used. The side wall 68 defines a centrallongitudinal axis 70 of the outer housing 62. The central longitudinalaxis 70 extends along the length L of the outer housing 62. The outerhousing 62 defines an interior space 72 of the exhaust treatment device23.

The exhaust treatment device 23 also includes a divider wall 74positioned within the interior space 72 of the outer housing 62. Thedivider wall 74 is positioned at an intermediate location along thelength L of the outer housing 62. The divider wall 74 separates theinterior space 72 of the outer housing 62 into a first region 76 and asecond region 78. The first region 76 is defined between the first endwall 64 and the divider wall 74. The second region 78 is defined betweenthe second end wall 68 and the divider wall 74. The doser 52 ispositioned in the first region 76, the NO_(x) treatment substrate 50 ispositioned in the second region 78, and the mixing arrangement 54 ispositioned between the doser 52 and the NO_(x) treatment substrate 50.

The device inlet 30 is in fluid communication with the first region 76of the interior space 72 and the device outlet 32 is in fluidcommunication with the second region 78 of the interior space 72. In apreferred embodiment, the device inlet 30 is defined through the sidewall 68 of the outer housing 62 and is configured for directing exhaustflow into the first region 76. It will be appreciated that the deviceinlet 30 can have a radial configuration, a tangential configuration oran angled configuration. Additionally, in other embodiments, the deviceinlet 30 can be an axial inlet defined through the first end wall 64.The device outlet 32 is shown being defined through the side wall 68 andis configured for receiving exhaust flow from the second region 78 andfor directing the exhaust flow out of the outer housing 62. Similar tothe device inlet, device outlet 32 can have a radial configuration, atangential configuration or an angled configuration. Additionally, inother embodiments, the device outlet 32 can have an axial configurationin which the device outlet 32 is defined through the second end wall 66.

The mixing arrangement 54 is part of an exhaust treatment and mixingassembly 80 positioned within the interior space 72. The exhausttreatment and mixing assembly 80 includes an inner conduit 82 (e.g., amixing tube) defining a mixing passage 84 that is coaxially aligned withthe central longitudinal axis 70 of the outer housing 62. The innerconduit 82 provides fluid communication between the first region 76 andthe second region 78 of the interior space 72. As shown at FIG. 1, theinner conduit 82 extends from a swirl chamber 86 of the mixingarrangement 54 to the divider wall 74. The inner conduit 82 providesfluid communication between the swirl chamber 86 and the second region78 of the interior space 72. The inner conduit 82 is attached to thedivider wall 74 adjacent an end 83 of the inner conduit 82. In oneembodiment, the divider wall 74 separates the first region 76 of theinterior space 72 from the second region 78 of the interior space 72such that only the mixing passage 84 provides fluid communicationbetween the first and second regions 76, 78.

The exhaust treatment and mixing assembly 80 further includes an outerconduit 88 that surrounds the inner conduit 82. An end 90 of the outerconduit 88 is attached to the first end wall 64 of the outer housing 62.An exhaust passage 92 is defined between the inner conduit 82 and theouter conduit 88. In one embodiment, the inner conduit 82 and the outerconduit 88 are cylindrical, and the exhaust passage 92 is annular. Inother embodiments, the inner and outer conduits 82 and 88 can be oval,rectangular, elliptical, or have other shapes. The exhaust passage 92 isconfigured to direct exhaust flow to the swirl chamber 86. The exhaustpassage 92 includes a first end 94 and an opposite second end 96. Thefirst end 94 is spaced from the divider wall 74 by a gap G which formsan axial spacing between the first end 94 and the divider wall 74. Thesecond end 96 is positioned adjacent the swirl chamber 86. An outerportion 98 of the first region 76 of the interior space 72 surrounds theouter conduit 88. The outer portion 98 is depicted as being annular inshape. The outer portion 98 of the first region 76 of the interior space72 defines a region for directing/transitioning exhaust flow from thedevice inlet 30 to the gap G. From the gap G, exhaust flows into theexhaust passage 92 through the first end 94. The exhaust then flowsthrough the exhaust passage 92 and exits the exhaust passage 92 throughthe second end 96 into the swirl chamber 86.

The exhaust treatment substrate 56 is positioned within the exhaustpassage 92. In one embodiment, exhaust treatment substrate 56 is acatalytic converter substrate. In another embodiment, the exhausttreatment substrate 56 is a flow-through filter substrate. Inembodiments that include an exhaust treatment substrate 56, it will beappreciated that the exhaust treatment substrate 56 provides someinitial treatment of the exhaust gas before the exhaust gas is directedto the swirl chamber 86.

The mixing arrangement 54 of the exhaust treatment and mixing assembly80 includes a swirl structure 102 positioned at the second end 96 of theexhaust passage 92. The swirl structure 102 preferably includes aconfiguration adapted for causing the exhaust flow that exits the secondend 96 of the exhaust passage 92 to swirl about the central longitudinalaxis 70 of the outer housing 62. In certain embodiments, the swirlstructure 102 can include scoops, baffles, vanes, deflectors, benttubes, angled tubes, or other structures adapted for causing the exhaustflow to rotate or swirl about the central longitudinal axis 70 withinthe swirl chamber 86. Example swirl structures are disclosed at U.S.Patent Publication Nos. US2011/0167810; US2010/0212301; andUS2009/0000287, which are hereby incorporated by reference in theirentireties.

The exhaust treatment and mixing assembly 80 further includes the doser52. Shown at FIG. 1, the doser 52 is mounted to the first end wall 64.In one embodiment, the doser 52 aligns with the central longitudinalaxis 70 of the outer housing 62. In use of the doser 52, reactant from areactant source 53 is dispensed (e.g., sprayed, injected, etc.) into theswirling exhaust within the swirl chamber 86. The swirling exhaustwithin the swirl chamber 86 provides turbulence for uniformly mixing thereactant in the exhaust. The swirling action is carried from the swirlchamber 86 into the mixing passage 84 of the inner conduit 82. Thus,mixing of the reactant with the exhaust continues as the exhaust flowsthrough the inner conduit 82. The swirling continues as the exhaustexits the inner conduit 92 and enters the second region 78 of theinterior space 72. An exhaust expansion region ER is defined between theinner conduit 82 and the NO_(x) treatment substrate 50. Uniform mixingof the reactant has preferably occurred by the time the exhaust reachesan upstream face 104 of the NO_(x) treatment substrate 50. By uniformlydistributing the reactant within the exhaust stream, the efficiency ofthe chemical reactions that take place at the NO_(x) treatment substrate50 can be optimized by ensuring that a maximum surface area of theNO_(x) treatment substrate 50 is used. After the exhaust passes througha downstream face 106 of the NO_(x) treatment substrate 50, the exhaustexits the outer housing 62 through the device outlet 32.

Referring to FIGS. 2-6, more detailed drawings of the exhaust treatmentdevice 23 are provided. As shown at FIG. 4, a reference bisection plane108 divides the outer housing 62 into a first half 110 and a second half112. The device inlet 30 and the device outlet 32 are preferably onopposite sides of the bisection plane 108. For example, the device inlet30 is shown at the first half 110 of the outer housing 62 and the deviceoutlet 32 is shown at the second half 112 of the outer housing 62. Inone embodiment, the device inlet 30 is closer to the first end wall 64than to the bisection plane 108.

Referring to FIG. 4, the device inlet 30 is shown including an inletpipe 114 that extends through the side wall 68. Inlet pipe 114 includesan inner end 116 in direct fluid communication with the outer portion 98of the first region 76 of the interior space 72. The inlet pipe 114 alsoincludes an outer end 118 adapted for connection to another pipe, suchas the exhaust conduit 21 (FIG. 1).

The device outlet 32 is shown including an outlet pipe 120 that extendsthrough the side wall 68. The outlet pipe 120 has an inner end 122 thatis mitered (i.e., cut at an angle). Outlet pipe 120 also includes anouter end 124 adapted for connection to a conduit such as the exhaustconduit 34.

Referring to FIGS. 4-6, the first end wall 64, the second end wall 66and the side wall 68 are preferably insulated. For example, each of thewalls 64, 66 and 68 has a multilayer construction including aninsulation layer sandwiched between an inner layer or wall and an outerlayer or a wall.

Referring to FIG. 4, the inlet pipe 114 has centerline 126 thatintersects the exhaust treatment substrate 56 and the inner conduit 82.In the depicted embodiment, the centerline 126 is aligned along a planeP that bisects the inner and outer conduits 82, 88 and intersects thecentral longitudinal axis 70 of the outer housing (see FIG. 6). In thedepicted embodiment, the inlet pipe 114 is located at an axial positionthat at least partially axially overlaps the outer conduit 88. Moreparticularly, the inlet pipe 114 is shown at an axial position thatcompletely axially overlaps the axial position of the outer conduit 88.In certain embodiments, at least a portion of the inlet pipe 114 islocated at an axial position that is axially between the first end 94 ofthe exhaust passage 92 and the first end wall 64. In certainembodiments, at least a portion of the inlet pipe 114 is axially closerto the first end wall 64 than the first end 94 of the exhaust passage 92of the depicted embodiment. The centerline 126 of the inlet pipe 114 isshown positioned at a first spacing S1 from the first end wall 64 thatis smaller than a second spacing S2 defined between the first end wall64 and the first end 94 of the exhaust passage 92. Because of thisconfiguration, at least a portion of the exhaust flow input into thefirst regions 76 through the inlet pipe 114 initially flows within theouter portion 98 along the flow path FP in a direction toward the secondend wall 66 before entering the gap G and reversing directions to flowthrough the exhaust passage 92 in a direction toward the first end wall64.

The flow routing path FP for the exhaust treatment device 23 is shown atFIG. 7. As shown at FIG. 7, the exhaust enters the interior space 72 ofthe outer housing 62 through the inlet pipe 114. Specifically, from theinner end 116 of the inlet pipe 114, the exhaust flows into the outerportion 98 of the first region 76 of the interior space 72. Within theouter portion 98, the exhaust flows along the flow path FP at leastpartially in a direction 128 oriented toward the second end wall 66 ofthe outer housing 62. Thus, the flow within the outer portion 98 isdirected toward the divider wall 74. The divider wall 74 directs theflow to the gap G. From the gap G, the exhaust flows through the exhaustpassage 92 and from the first end 94 toward the second end 96. Theexhaust within the passage 92 flows through the exhaust treatment device56 and flows at least partially in a direction 129 oriented toward thefirst end wall 64. At the second end 96, the swirl structure 102 causesthe exhaust exiting the exhaust passage 92 to be swirled within theswirl chamber 86 about the central longitudinal axis 70.

The doser 52 injects reactant into the swirling exhaust within the swirlchamber 86. The swirling exhaust within the swirl chamber 86 flows intothe mixing passage 84 and flows back toward the second end wall 66 atleast partially in the direction 128. As the exhaust flows in the mixingpassage 84, the swirling motion generated by the swirl structure 102 ismaintained. The swirling exhaust flows through the mixing passage 84 andexits the end 83 of the inner conduit 82 into the expansion region ERdefined by the second region 78 of the interior space 72. The exhaust,with the reactant contained therein, then flows through the NO_(x)treatment substrate 50 where at least a portion if the NO_(x) within theexhaust is removed from the exhaust stream. After passing through theNO_(x) treatment substrate 50, the exhaust flows through a transitionspace 137 defined between the downstream face 106 of the NO_(x)treatment substrate 50 and the second end wall 66 of the outer housing62. From the transition space 137, the exhaust enters the inner end 122of the outlet pipe 120 and exits the exhaust treatment device 23 throughthe outlet pipe 120.

FIG. 8 shows the exhaust treatment device 23 of FIGS. 2-6 with theaddition of an extra swirl structure 131 positioned between the dividerwall 74 and the upstream face 104 of the NO_(x) treatment substrate 50.The swirl structure 131 is adapted for providing the exhaust withadditional swirling action in the expansion region ER between thedivider wall 74 and the upstream face 104 of the NO_(x) treatmentsubstrate 50. As shown, the swirl structure 131 includes a plate 133defining swirl elements 130 for generating the swirling action. It willbe appreciated that the swirl elements 130 can include louvers, scoopsor any of the other swirl structures identified above.

FIG. 9 shows the exhaust treatment device 23 of FIGS. 2-6 modified toinclude an additional mixing structure 140 between the divider wall 74and the upstream face 104 of the NO_(x) treatment substrate 50. Themixing structure 140 includes a housing 142 having a perforated sidewall 144 that surrounds the central longitudinal axis 70 and an end cap146 that encloses an axial end of the housing 142. The mixing structure140 also includes an extension 147 that extends outwardly from the innerconduit 82 along the central longitudinal axis 70. A first end 148 ofthe extension 147 receives flow from the inner conduit 82 while anopposite second end 149 directs exhaust flow into the interior of thehousing 142. The second end 149 of the extension 147 can have abell-mouthed configuration. In use of the mixing structure 140, exhaustfrom the inner conduit 82 flows through the extension 147 and enters thehousing 142 through the bell-mouth of the extension 147. The flow thenreverses directions and exits the housing 142 through the perforatedside wall 144. Perforations in the perforated side wall 144 assist indistributing the flow uniformly across the upstream face 104 of theNO_(x) treatment substrate 50. The perforations can include openings,slots, louvers or other structures.

FIGS. 10 and 11 depict a second exhaust treatment device 23A inaccordance with the principles of the present disclosure. The exhausttreatment device 23A includes an outer housing 62A enclosing a NO_(x)treatment substrate 50A, a divider wall 74A, an inner conduit 82A, anexhaust treatment substrate 56A that surrounds the inner conduit 82A, aswirl chamber 86A, and a swirl structure 102A. The outer housing 62Aincludes a first end wall 64A and a second end wall 66A. A dosermounting location is provided at the center of the first end wall 64A.An outlet pipe 120A is provided at the center of the second end wall66A. The outlet pipe 120A provides the exhaust treatment device with anaxial outlet. An inlet pipe 114A is mounted through a side wall 68A ofthe housing 62A. A centerline 126A of the inlet pipe 114A intersects theinner conduit 82A and also intersects a gap G defined between thedivider wall 74A and the exhaust treatment substrate 56A. The inlet pipe114A is positioned at an axial position aligned between the divider wall74A and the exhaust treatment substrate 56A. As shown at FIG. 11, theinlet pipe 114A is fully axially offset from the exhaust treatmentsubstrate 56A and aligns with the gap G. Still referring to FIG. 11, aline FPA shows an example flow path through the exhaust treatment device23A.

FIGS. 12-18 show a third exhaust treatment device 23B in accordance withthe principles of the present disclosure. The exhaust treatment device23B has generally the same configuration as the exhaust treatment device23, except divider wall 74B has more of a domed configuration ascompared to the divider wall 74. A concave side of the divider wall 74Bfaces toward the NO_(x) treatment device.

FIGS. 19-21 show a fourth exhaust treatment device 23C in accordancewith the principles of the present disclosure. It will be appreciatedthat the exhaust treatment device 23C has a similar configuration as theexhaust treatment device 23. However, the exhaust treatment device 23Chas an inlet pipe 114C that is closer to a first end wall 64C ascompared to the spacing between the inlet pipe 114 and the first endwall 64. Additionally, the inlet pipe 114C has a tapered configurationadjacent an inner end 116C of the inlet pipe 114C. As shown at FIG. 20,the inlet pipe 114C tapers inwardly toward a central axis 126C of theinlet pipe 114C as the inlet pipe 114C extends toward the interior ofthe exhaust treatment device 23C. Also, as shown at FIG. 21, the inletpipe 114C tapers outwardly from the central axis 126C as the inlet pipe114C extends toward the interior of the exhaust treatment device 23C.This tapered configuration of the inlet pipe 114C provides the inletpipe 114C with an elongate transverse cross-sectional shape. It is alsonoted that the exhaust treatment device 23C includes an outlet pipe 120Cthat is not mitered. Instead, the outlet pipe 120C has a perforatedsection 49 for receiving exhaust flow from the interior of the exhausttreatment device 23C.

FIGS. 22-24 show a fifth exhaust treatment device 23D in accordance withthe principles of the present disclosure. The exhaust treatment device23D has the same configuration as the exhaust treatment device 23Cexcept the exhaust treatment device 23D has an axial outlet pipe 120D(FIG. 23).

FIGS. 25-32 illustrate a sixth exhaust treatment device 23E inaccordance with the principles of the present disclosure. The exhausttreatment device 23E is similar in many respects with respect to thepreviously described embodiments. However, the exhaust treatment deviceincludes a divider wall 74E that provides a gradual diameter transitionfrom an end of an inner conduit 82E to an upstream face 104E of a NO_(x)treatment substrate 50E. Also, the exhaust treatment device 23E includesan inlet pipe 114E having a bent or angled configuration. The inlet pipe114E is mounted at an axial location that only partially overlaps anexhausts treatment substrate 54E of the exhaust treatment device 23E.Additionally, the exhaust treatment device 23E includes an outlet pipe120E that is angled relative to a side wall 68E of the exhaust treatmentdevice 23E and that is reinforced by a reinforcing bracket 150E (FIGS.28 and 32). The outlet pipe 120E has an outer end that is tapered andsegmented. A generally rectangular mounting flange 154 is used to securethe outlet pipe 120E to a side wall 68E of an outer housing 62E of theexhaust treatment device 23E.

FIGS. 33-38 illustrate a seventh exhaust treatment device 23F inaccordance with the principles of the present disclosure. The exhausttreatment device 23F has many of the same features described in theprevious embodiments. However, the exhaust treatment device 23F includesa structure for enhancing the mixing volume through which the exhaustmust pass before reaching an upstream face 104F of a NO_(x) treatmentsubstrate 50F. For example, the exhaust treatment device includes adivider wall 74F attached to an end 83F of an inner conduit 82F defininga mixing passage 84F. A baffle plate 160 is mounted downstream of thedivider wall 74F. The baffle wall 160 diverts flow from the mixingpassage 84F radially outwardly toward a serpentine passage arrangement162. As used herein, “serpentine passage” means a path that doubles backon itself at least once. The serpentine passage arrangement 162 includesan outer annular passage 163 that extends from the baffle 160 toward asecond end wall 66F of the exhaust treatment device 23F. The outerannular passage 163 is defined in part by a cylindrical wall 164. Thecylindrical wall 164 defines a plurality of openings 165 that providefluid communication between the outer passage 163 and an inner passage166. An end wall 168 blocks the ends of the passages 163, 166 to preventflow from bypassing the NO_(x) treatment substrate 50F.

As shown by flow path FPF, in use, exhaust flow exiting the innerconduit 82F is directed by the baffle 160 radiating outwardly to theouter passage 163. Flow proceeds along the outer passage 163 toward thesecond end wall 66F. Flow then proceeds through the openings 165 intothe inner passage 166. Once within the inner passage 166, the flowproceeds back toward a first end wall 64F of the exhaust treatmentdevice 23F. Upon exiting the inner passage 166, the exhaust flow entersthe NO_(x) treatment substrate 50F through an upstream face 104F of theNO_(x) treatment substrate 50F. The flow then proceeds through theNO_(x) treatment substrate 50F and subsequently exits the exhausttreatment device 23F through an outlet pipe 120F.

FIGS. 39-45 show an eighth exhaust treatment device 23G in accordancewith the principles of the present disclosure. The exhaust treatmentdevice 23G has many of the same features described with respect toprevious embodiments. However, unlike the previous embodiments, thedevice 23G has an outer housing 62G has a stepped configurationincluding an enlarged diameter portion 180 and a reduced diameterportion 182. Inlet and outlet pipes 114G and 120G are mounted throughthe enlarged diameter portion 180. A first end wall 64G is mounted tothe reduced diameter portion 182 and a second end wall 66G is mounted tothe enlarged diameter portion 180. A doser mounting location is providedat the first end wall 64G. An exhaust treatment substrate 56G, an innerconduit 82G and a swirl structure 102G are mounted within the reduceddiameter portion 182. Similarly, a swirl chamber 86G is provided withinthe reduced diameter portion 182. A NO_(x) treatment substrate 50G ismounted within the enlarged diameter portion 180. The outlet pipe 120Ghas a radial configuration and projects laterally outwardly from theenlarged diameter portion 180. A central axis of the outlet pipe 120Gintersects a longitudinal centerline 70G of the exhaust treatment device23G. The inlet pipe 114G has a tangential configuration. A centerline126G of the inlet pipe 114G is laterally offset from the centrallongitudinal axis 70G of the exhaust treatment device 23G. Thecenterline 126G of the inlet pipe 114G does not intersect the exhausttreatment substrate 56G or an inner conduit 82G of the exhaust treatmentdevice 23G. The inlet pipe 114G is mounted at a location that partiallyaxially overlaps the exhaust treatment substrate 56G. The centerline ofthe inlet pipe 114G intersects a gap G defined between the exhausttreatment substrate 56G and the divider wall 74G.

FIGS. 46 and 47 show a ninth exhaust treatment device 23H in accordancewith the principles of the present disclosure. The exhaust treatmentdevice 23H has many of the same features and structures described withrespect to previous embodiments. However, the exhaust treatment device23H includes an inlet pipe 114H having an inner end 116A that is angledrelative to a side wall 68H of the exhaust treatment device 23H. Theinlet pipe 114H also is bent such that an outer end of the inlet pipe114H defines an axis 300 that is parallel to a central longitudinal axis70H of the exhaust treatment device 23H. Exhaust treatment device 23Halso includes an outlet pipe 120H mounted to a second end wall 66H ofthe exhaust treatment device 23H. The outlet pipe 120H has a miteredinner end 122H attached to the second end wall 66H. Additionally, theoutlet pipe 120H is straight and defines a centerline that is angledrelative to the second end wall 66H.

It has been determined that the NO_(x) conversion efficiency at theNO_(x) treatment substrate is dependent on the level ofmixing/turbulence (e.g., swirl rate) and the mixing volume definedbetween the dispenser mounting location and the upstream face of theNO_(x) treatment substrate. In this regard, increased turbulence ratesprovide improved NO_(x) conversion at the NO_(x) treatment substrate.Also, larger mixing volumes and/or residence times (mixing volume/ratedflow) also provide improved NO_(x) conversion at the NO_(x) treatmentsubstrate. FIG. 48 is a graph that demonstrates this relationship. Thesolid lines correspond to normal turbulence (e.g., swirl) and the dashedlines correspond to increased turbulence (e.g., swirl). The test data isfor a 6.6 L heavy duty diesel engine used on a treatment system having aDOC positioned upstream from the mixing volume and the NO_(x) treatmentsubstrate. NRSC represents the Non Road Stationary Cycle testingprotocol. NRTC represents the Non Road Transient Cycle testing protocol.LT represents four low temperature modes at 230-250 degrees Celsius.

It will be appreciated that embodiments of the present disclosureprovide compact arrangements that also have aggressivemixing/turbulence/swirling structures and relatively large mixingvolumes/residence times. For example, FIG. 49 shows a mixing volume MVfor the exhaust treatment device 23A of FIG. 11. As shown at FIG. 49, anexpansion region ERA between the divider plate 74A and the NO_(x)treatment substrate 50A greatly increases the mixing volume MV withoutadding a significant amount to the overall length of the exhausttreatment device 23A. By using supplemental mixers of the type shown atFIGS. 8 and 9, the volume corresponding to the expansion region ERA caneven more effectively be used. Additionally, mixing volume extenders ofthe type shown in the embodiment of FIG. 35 can further enlarge themixing volume so as to improve NO_(x) conversion efficiencies at theNO_(x) treatment substrate.

A selective catalytic reduction (SCR) catalyst device is typically usedin an exhaust system to remove undesirable gases such as nitrogen oxides(NOx) from the vehicle's emissions. SCR's are capable of converting NOxto nitrogen and oxygen in an oxygen rich environment with the assistanceof reactants such as urea or ammonia, which are injected into theexhaust stream upstream of the SCR through the doser 52.

A lean NOx catalyst device is also capable of converting NOx to nitrogenand oxygen. In contrast to SCR's, lean NOx catalysts use hydrocarbons asreducing agents/reactants for conversion of NOx to nitrogen and oxygen.The hydrocarbon is injected into the exhaust stream upstream of the leanNOx catalyst. At the lean NOx catalyst, the NOx reacts with the injectedhydrocarbons with the assistance of a catalyst to reduce the NOx tonitrogen and oxygen. While the exhaust treatment system is described asincluding an SCR, it will be understood that the scope of the presentdisclosure is not limited to an SCR as there are various catalystdevices, such as those described below, that can be used in accordancewith the principles of the present disclosure.

Lean NOx traps use a material such as barium oxide to absorb NOx duringlean burn operating conditions. During fuel rich operations, the NOx isdesorbed and converted to nitrogen and oxygen by reaction withhydrocarbons in the presence of catalysts (precious metals) within thetraps.

Catalytic converters (diesel oxidation catalysts or DOC's) are typicallyused in an exhaust system to convert undesirable gases such as carbonmonoxide and hydrocarbons from a vehicle's exhaust into carbon dioxideand water. DOC's can have a variety of known configurations. Exemplaryconfigurations include substrates defining channels that extendcompletely therethrough. Exemplary catalytic converter configurationshaving both corrugated metal and porous ceramic substrates/cores aredescribed in U.S. Pat. No. 5,355,973, which is hereby incorporated byreference in its entirety. The substrates preferably include a catalyst.For example, the substrate can be made of a catalyst, impregnated with acatalyst or coated with a catalyst. Exemplary catalysts include preciousmetals such as platinum, palladium and rhodium, and other types ofcomponents such as base metals or zeolites.

Diesel engine exhaust contains particulate matter, the emission of whichis regulated for environmental and health reasons. This particulatematter generally constitutes a soluble organic fraction (“SOF”) and aremaining portion of hard carbon. The soluble organic fraction may bepartially or wholly removed through oxidation in an oxidation catalystdevice such as a catalytic converter; however, this typically results ina reduction of only about 20 percent of total particulate emissions orless.

In one non-limiting embodiment, a catalytic converter can have a celldensity of at least 200 cells per square inch, or in the range of200-400 cells per square inch. A preferred catalyst for a catalyticconverter is platinum with a loading level greater than 30 grams/cubicfoot of substrate. In other embodiments the precious metal loading levelis in the range of 30-100 grams/cubic foot of substrate. In certainembodiments, the catalytic converter can be sized such that in use, thecatalytic converter has a space velocity (volumetric flow rate throughthe DOC/volume of DOC) less than 150,000/hour or in the range of50,000-150,000/hour.

Flow-through filters partially intercept solid PM particles in exhaust.Some flow-through filters may exhibit a filtration efficiency of 50% orless. Certain flow-through filters do not require all of the exhaust gastraveling through the filter to pass through a filter media having apore size sufficiently small to trap particulate material. Oneembodiment of a flow-through filter includes a plurality of flow-throughchannels that extend longitudinally from the entrance end to the exitend of the flow-through filter. The flow-through filter also includesfilter media that is positioned between at least some of theflow-through channels. The filter further includes flow diversionstructures that generate turbulence in the flow-through channels. Theflow diversion structures also function to divert at least some exhaustflow from one flow-through channel to another flow-through channel. Asthe exhaust flow is diverted from one flow-through channel to another,the diverted flow passes through the filter media causing someparticulate material to be trapped within the filter media. Thisflow-through-type filter yields moderate filtration efficiencies,typically up to 50% per filter, with relatively low back pressure.

A catalyst coating (e.g., a precious metal coating) can be provided onthe flow-through channels of the flow-through filter to promote theoxidation of the soluble organic fraction (SOF) of the particulatematter in the exhaust or to promote the oxidation of certain gases. Toenhance to combustion of carbon at the filter media, the filter mediacan also be coated with a catalyst (e.g., a precious metal such asplatinum).

Diesel particulate filters (DPF) are configured to remove particulatematerial from an exhaust stream by mechanical filtration such thatparticulate matter (e.g., hard carbon) is collected within the dieselparticulate filters. Diesel particulate filters can be catalyzed tofoster the oxidation of SOF or other contaminants. Diesel particulatefilters typically need to be regenerated through a process wherematerial collected therein is removed through a combustion process. Anexample diesel particulate reduction device is a wall-flow filter havinga monolith ceramic substrate including a “honey-comb” configuration ofplugged passages as described in U.S. Pat. No. 4,851,015 that is herebyincorporated by reference in its entirety. Example materials formanufacturing the substrate include cordierite, mullite, alumina, SiC,refractory metal oxides, or other materials conventionally used ascatalyzed substrates. Such filters generally have particulate filtrationefficiencies greater 75 percent and typically greater than 90 percent.

In many of the above embodiments, a doser is not shown. Instead,generally triangular doser mounting locations are provided at the firstend walls of such embodiments. It will be appreciated that in use,dosers are mounted at such locations.

While the exhaust treatment substrate positioned downstream from themixing arrangement and doser is repeatedly referred to as a NO_(x)treatment substrate, it will be appreciated that such substrate can alsobe referred to generally as an “exhaust treatment substrate” since inother embodiments in accordance with the principles of the presentdisclosure the substrate can be adapted for removing/reducingcontaminants other than NO_(x) and the doser 52 can be adapted fordelivering reactants suitable for promoting the removal of suchalternative contaminants.

In other embodiments, the exhaust treatment substrate positioneddownstream of the doser can include the combination of a DOC positionedupstream from a DPF. In such embodiments, the doser can dispense areactant such as fuel that is combusted at the DOC thereby generatingheat for regenerating the DPF by combusting particulate matter collectedon the DPF. Various modifications and alterations of this disclosurewill become apparent to those skilled in the art without departing fromthe scope and spirit of this disclosure, and it should be understoodthat the scope of this disclosure is not to be unduly limited to theillustrative embodiments set forth herein.

What is claimed is:
 1. An exhaust treatment device comprising: an outerhousing including opposite first and second end walls and a length thatextends between the first and second end walls, the outer housing alsoincluding a side wall that extends along the length from the first endwall to the second end wall, the outer housing defining an interiorspace; a divider wall within the interior space of the outer housing,the divider wall being positioned at an intermediate location along thelength of the outer housing, the divider wall separating the interiorspace of the outer housing into a first region and a second region; adevice inlet that is in fluid communication with the first region of theinterior space; a device outlet that is in fluid communication with thesecond region of the interior space; an exhaust treatment and mixingassembly including: a swirl chamber positioned within the first regionof the outer housing; a mixing passage defined by an inner conduit thatextends along the length of the outer housing, the mixing passageproviding fluid communication between the swirl chamber and the secondregion of the interior space; an exhaust passage that surrounds theinner conduit, the exhaust passage being configured to direct exhaustflow into the swirl chamber; a swirl structure for swirling the exhaustflow directed from the exhaust passage into the swirl chamber; and adispenser mounting location disposed within the first region of theouter housing for mounting a dispenser used for dispensing a reactantinto the swirl chamber.
 2. The exhaust treatment device of claim 1,further comprising a diesel particulate filter positioned downstream ofthe first region.
 3. The exhaust treatment device of claim 1, whereinthe first region is defined between the divider wall and the first endwall.
 4. The exhaust treatment device of claim 1, wherein the secondregion is defined between the divider wall and the second end wall. 5.The exhaust treatment device of claim 1, wherein the device inlet isdefined through the side wall of the outer housing.
 6. The exhausttreatment device of claim 1, wherein the device outlet is definedthrough the side wall of the outer housing.
 7. The exhaust treatmentdevice of claim 1, wherein the device outlet is defined through thesecond end wall of the outer housing.
 8. The exhaust treatment device ofclaim 1, wherein the exhaust passage the surrounds the inner conduit hasan inlet end spaced from the divider wall by an axial gap.
 9. Theexhaust treatment device of claim 1, wherein an upstream face of theexhaust treatment substrate is spaced less than 750 millimeters from thedispenser mounting location.
 10. The exhaust treatment device of claim1, wherein the device inlet is provided at an axial position that atleast partially axially overlaps the inner conduit.
 11. The exhausttreatment device of claim 1, further comprising an exhaust treatmentsubstrate mounted in the second region of the interior space.
 12. Theexhaust treatment device of claim 11, wherein the exhaust treatmentsubstrate includes a NOx treatment substrate.
 13. The exhaust treatmentdevice of claim 1, wherein the dispenser mounting location is disposeddownstream of the exhaust passage and upstream of the mixing passage.14. The exhaust treatment device of claim 13, wherein the dispensermounting location is disposed within the swirl chamber.
 15. The exhausttreatment device of claim 1, further comprising a second swirl structuredisposed in the second region of the outer housing.
 16. The exhausttreatment device of claim 15, further comprising an exhaust treatmentsubstrate disposed downstream of the second swirl structure.
 17. Theexhaust treatment device of claim 15, wherein the second swirl structureincludes a plate with scoops.
 18. The exhaust treatment device of claim1, further comprising an annular exhaust treatment substrate positionedwithin the exhaust passage for treating the exhaust that flows throughthe exhaust passage.
 19. The exhaust treatment device of claim 18,wherein the annular exhaust treatment substrate includes a catalyticconverter substrate.
 20. The exhaust treatment device of claim 18,wherein the annular exhaust treatment substrate includes a flow-throughfilter substrate.